This invention relates to the field of litter collection, and in particular to machines that pick up bottles and cans.
Prior art litter collection machines have been designed to operate in a horizontal plane to clean streets, parks, parking lots and other recreational areas. No litter collection machine has addressed the problem of collecting litter on sloping terrain such as ditches along streets and highways and recreational areas where there is a severe undulating terrain.
The problem with prior art litter collection machines is that the collection apparatus, whether it is rollers or brushes is constrained to a horizontal plane of operation, thereby rendering the machine ineffective for litter pick up in ditches or severe undulating terrain. Another problem with prior art litter collection machines is that they are large with high centers of gravity causing the machine to be unstable on sloping terrain. Another problem with the prior art are the complex and expensive conveyor systems utilized to move litter from the pick-up means to the storage area thereby increasing machine costs.
Another problem with prior art litter pickup machines is that the "fingers" that make contact with the litter to sweep or pick up the litter often fail to engage or retain bottles and cans for subsequent removal. Consequently, some bottles and cans remain on the ground.
Examples of prior art devices include those disclosed in the following U.S. patents:
U.S. Pat. No. 4,593,426 discloses a litter collection machine with retrieval means including a roller with projections to remove surface litter and an adjustable mounting apparatus whereby the retrieval means may be moved toward or away from the surface. One problem with this machine is that the machine is large and has a high center of gravity thereby making it susceptible to "tipping over" when traveling perpendicular to the direction of slope of a hill or ditch. Another problem is that the projections are not efficient in picking up bottles and cans but rather intended to pick up paper and other light trash. Another problem is that the machine utilizes a complex conveyor system to elevate litter to a storage hopper thereby contributing to the machines high center of gravity and an elevated cost of purchase.
U.S. Pat. No. 4,550,465 discloses a litter collection machine with tandem rollers each having ground engaging rows of resilient fingers. The fingers spread apart to entrap litter and mesh between the rollers to transfer litter downstream to a main frame conveyor for containment within a trash drum. A pair of wiper blades remove entrapped litter between the fingers and provide a transfer path for the litter to the trash drum.
U.S. Pat. No. 4,290,820 discloses a front-end loader machine for collecting material on a roadway surface with a rotating brush on each front side touching the roadway surface to sweep material into a scraper blade. The scraper blade moves the collected material to an elevator assembly that elevates the collected material to a rear overhead discharge position for collection in a trailing hopper.
U.S. Pat. No. 4,214,336 discloses a litter collection machine including a self-propelled vehicle having a receiving tank mounted to the vehicle's frame and three spiked rollers attached to the rear end of the vehicle to pick up litter and feed the litter on a conveyor assembly that elevates the litter into an opening in the rear end of the receiving tank.
U.S. Pat. No. 3,807,154 discloses a litter collection system including a single large drum pulled behind a self-propelled vehicle with spring loaded fingers attached to the surface of the drum to engage litter articles. Once the fingers engage the litter, the drum rotates and positions the engaged litter above a collection basket where the litter is disengaged from the fingers by strippers that force the litter into the collection basket.
U.S. Pat. No. 3,777,327 discloses a litter collection machine that is self-propelled with a rotating drum to which flexible flaps are attached to pick up litter and deposit the litter upon a conveyor. The conveyor allows small stone and dirt to drape from the heavier litter, with the heavier litter being transported to a hammer mill and conveying structure that upwardly conveys the heavier litter to an elongated storage bin.